ROCHESTER, Minn. — By Nov. 10 in the terrible year that was 1918, things in Minnesota were looking a lot like they look today.

The newspapers were full of stories about pandemic case numbers climbing, while health officials were arguing over the best approach to combat the virus. But instead of COVID-19, the deadly outbreak back then was the Great Influenza, otherwise known as the Spanish Flu.

And instead of Republicans versus Democrats, the dividing line was one of geography, with Minneapolis intent on fighting the pandemic by shutting down gathering spots, while St. Paul wanted to focus on isolating the sick. Minneapolis eventually won that battle. By Nov. 10, schools, churches, theaters and public meeting places were ordered closed in both cities until deaths dropped below 49 a week, a goal that, at 120 deaths a week, seemed nowhere in sight.

Then as it is now, open defiance of health orders was commonplace, delaying progress: Football teams defied orders against playing in front of Minneapolis crowds, forcing police to come break up games in mid-play. Over in neighboring St. Paul, proprietors of theaters, pool halls, saloons and the trade union were arguing for reopening.

One thing all held in agreement -- no one liked the order keeping the streetcar windows open.

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"Another difficulty is that of keeping the required number of windows open," as the Minneapolis Sunday Tribune reported on Oct. 27, describing the mandate requiring fresh air on the network of railcars that criss-crossed the city. "There are persons who insist on closing them when the conductor is not near." As it turns out, the flu may have been deadly, but some passengers had gotten colds.

In a compromise, the Minneapolis health commissioner decided "street car windows will be kept open until the temperature drops to the freezing point, when they will be closed if the car is heated and a ventilation system is installed."

The value of fresh air, then and now

The nation had known for weeks that "the value of fresh air through open windows can not be overemphasized," as the Bemidji Pioneer noted in a front-page story entitled "Uncle Sam's Advice on the Flu."

Experts even advised giving school children extra credit for sleeping with the windows open.

All this may seem like ancient history now, what with decades of obsessive attention to keeping windows closed and shutting off leaks in the name of energy efficiency, but opening windows is officially back in style. In fact, some believe the "ventilation" of stale indoor air should be pushed to the top of the list for steps to be adopted to reduce the spread of COVID-19.

Even in winter. Especially in winter.

This week, the German Chancellor Angela Merkel promoted the opening of windows on the hour as "one of the cheapest and most effective ways" of containing the virus. Germans already were used to the practice of opening windows once in the morning and once at night. Now schools in that nation are being asked by official health guidance papers to bring in a draft for three to five minutes, every 15 to 20 minutes.

The idea is that three V's determine spread: venue, vocalization and ventilation. We already know about the first two: How indoor dining is known to be riskier than outdoor patios, and how singing, loud talking and yelling is more dangerous than muted conversation.

But ventilation remains an afterthought. In America, the Centers for Disease Control and Prevention buries the tip on a list of mitigation suggestions for businesses, homes, schools and workplaces, saying only that we should "Increase ventilation by opening windows or adjusting air conditioning."

Does it work? They sure thought so in the aftermath of SARS.

"Improvements in air-handling equipment, portable filtration units, and the introduction of physical barriers in the form of partitions or doors may offer some protection," wrote the authors of a 2009 article in the American Journal of Public Health entitled "Open Air Treatment of Pandemic Influenza."

"However," they added, "more might be gained by introducing high levels of natural ventilation or, indeed, by encouraging the public to spend as much time outdoors as possible."

The authors even said "it might also be prudent to stockpile tents and beds, because hospitals in the United Kingdom, the United States, and elsewhere are not prepared for a severe pandemic. Temporary accommodation would be required to deal with the most seriously ill, just as it was in 1918."

"It certainly is consistent with the idea of increased air flow," said Minnesota director of infectious disease Kris Ehresmann, during a recent press call. Ehresmann remembers how during her travels to Germany as a child the locals would put pillows outside at the end of each day. "Right now there's nothing imminent that would provide that sort of guidance (in Minnesota)," she said, "but its consistent with the benefits of being outside."

Schools, homes, aerosols and trombones

Suo Yang, of the University of Minnesota, has studied the movement of air particles as it relates to the risk of getting COVID-19 indoors. He's learned that teachers should stand under air vents, that hotels have some of the worst ventilation of indoor places, and he's studied the effects of brass and woodwind sections on air flow for fans of the Minnesota Orchestra worried about catching COVID-19 while listening to Mozart.

He says the best air flow system can't match the simple act of throwing open the windows.

"I think it definitely helps," he says. "For indoors, the key thing is typically people eject aerosols faster than can be removed by ventilation." These aerosols are not getting dispersed and diluted in air filtration systems, Yang says.

"The very good thing about a window is even if the flow rate is low, the area is huge, compared to a normal HVAC system ... That makes the probability the stream line gets to go out that much higher."

So, should opening the windows twice on the hour become ordered by official decree?

"We don't actually need the government to tell us everything," Yang says. "Whatever makes sense to people, they should go do it. We can't wait for CDC for every detail. We are not in kindergarten."